1. Field of the Invention
The present invention relates to a device to feed ribbon-like trimmings under the presser foot of a sewing machine, of the type comprising at least a support arm fastened to the sewing machine, a feed roller rotatably engaged with the support arm and extending before the presser foot of the sewing machine according to an axis at right angles to the feed advance direction of the workpiece, a motor to rotate the feed roller, at least two guides, each of them extending upwardly from the feed roller and slidably engaging a piece of trimmings to guide it towards the feed roller and pressure means acting in abutment relationship with the feed roller to push one of said trimmings against the feed roller itself so that it may be pulled by said feed roller as a result of the rotational movement imparted thereto.
In greater detail, the present device is adapted to be associated with sewing machines for industrial use to automatically carry out the selective feeding of two different elastic bands or strips or other ribbon-like trimmings.
2. Prior Art
It is known that there are industrial sewing machines which with the aid of appropriate feeding devices are capable of applying an elastic strip or other ribbon-like trimmings (such as tapes, neck-bands and the like) to a workpiece while a line of stitching is being performed.
According to one of said known feeding devices, it is provided the use of a feed roller which, by a support arm fixedly fastened to the sewing machine, is rotatably held up before the presser foot in a slightly raised position with respect to the workpiece-supporting table. In greater detail, the feed roller extends according to an axis at right angles to the advance direction of the workpiece on the supporting table and can be rotated about its own axis upon command of a motor or by other driving gears connected to the actuating members of the sewing machines.
Associated with the feed roller is a pressure backing roller which is elastically urged against the feed roller. The piece of trimmings running along one or more guides extending from the feed roller and backing roller, engages between these rollers and by effect of the rotation imparted to the feed roller, is fed under the presser foot while the stitching is being executed.
Although these devices have been successful in carrying out the application of trimmings to a workpiece, it has been found that their use involves some difficulties when two different types of trimmings have to be selectively fed. This requirement for example occurs in the manufacture of underclothing garments when which elastic strips or bands of two different widths or colors must be inserted.
In these cases the described devices are not very pratical in use. In fact each time it is necessary to replace the trimmings to be applied to the workpiece, the operator must manually disengage the previously used trimmings from the feed roller and pressure backing roller and engage the new trimmings to apply during the execution of the subsequent line of stitching, between said two rollers.
Due to this necessity, above all when mass-produced garments are concerned there are rather long down times and as a result the cost of the finished articles is increased.